monitor wipes
post its of various sizes
markers
pens
sign holders
candy for help desk / registration desk

Where would this fit under https://www.mediawiki.org/wiki/User:Sonkiki/Hackathons/handbook ?

I'd put it under "during the event", in a section called "packing list", and/or under "venue + wifi".

... and I will make sure to put it there. :)

painters tape (to stick signs to the wall without damaging it)
signs for the wall: social media details, FSP details, venue maps, skill share wall
scissors
extra power adaptors if possible
projector connections of various types if the venue does not provide this
stickers / branded give-aways
colorful pens for sign design